In a wireless communication system, in general, a master communication device determines a wireless channel to be allocated to a slave communication device. Then, the master communication device transmits a control message including channel allocation information indicating the wireless channel to the slave communication device.
For example, in extended Global Platform (XGP) that employs an orthogonal frequency division multiple access (OFDMA) method and a time division multiple access/time division duplex (TDMA/TDD) method, the control message illustrated in FIG. 9 is transmitted from a base station to a mobile station for each frame (see, for example, Non-patent Document 1).
In the control message illustrated in FIG. 9, a “MAP” corresponds to the channel allocation information. The MAP is information indicating presence/absence of allocation of each of a plurality of wireless channels to the mobile station, which are predefined for a predetermined frequency band. Here, the MAP is a 72-bit bitmap in which, of 72 wireless channels, the wireless channel allocated as a communication channel is indicated as “1” and the wireless channel that is not allocated as the communication channel is indicated as “0”. Further, an “ACK” is information indicating presence/absence of an error in each of user data pieces transmitted from the mobile station via the communication channel. The ACK is a 36-bit bitmap in which, of the user data pieces subjected to error detection for every two wireless channels adjacent to each other in a frequency direction, the user data piece from which no error has been detected is indicated as “1” and the user data piece from which an error has been detected is indicated as “0”. A “V” is information indicating a maximum number of wireless channels that can be allocated in each of a plurality of time slots.